The present invention relates to surveying elevator hoistways, in particular, to methods of and devices for performing such surveys.
The use of elongated rails to guide or support elevator cars is well known in the art. Elevator systems typically employ two rails arranged on opposite sides of the elevator car and running the entire length of the elevator hoistway. The elevator car, typically suspended by steel ropes or belts from the upper end of the hoistway, or by a hydraulic piston arranged at the hoistway bottom, is guided by the rails as it traverses the hoistway. Even slight deflections in rail segments or discontinuities between the segments may cause the traveling elevator car to sway or vibrate as it traverses the hoistway.
Properly aligning the rails in the hoistway to guard against rail imperfections depends in large part on deviations in the vertical walls of the hoistway to which the rails are attached. Surveying elevator hoistways is a time consuming, manual, and costly task in new elevator installations and modernizations of existing elevator systems. Hoistways are commonly surveyed manually by: (a) establishing a vertical reference, or plumb line, such as a weighted rope or cable hung from the top of the hoistway; and (b) manually measuring the horizontal distance between the plumb line and each of the four vertical hoistway walls at each floor landing. Prior hoistway surveying tools and methods are not only time consuming and costly, but are also subject to relatively large margins of error.
In light of the foregoing, the present invention aims to resolve one or more of the aforementioned issues that can affect elevator systems.